The use of removable plugs to prevent access to the line terminals of industrial-rated circuit breakers is described in U.S. Pat. No. 4,754,247 wherein the removable plugs are inserted in the circuit breaker cover within the access holes to the line terminals. The plugs are removed when connecting the circuit breakers within an electrical distribution circuit and are later replaced to prevent accidental contact with the energized line terminals.
When a compact current limiting circuit breaker, such as that described within U.S. patent application Ser. No. 344,936 filed Apr. 28, 1989 and entitled "Compact Current Limiting Circuit Breaker" is used within an industrial power distribution circuit, intense arc gases are generated during overcurrent interruption. This Application should be reviewed for its teachings of an arc chute arrangement for rapidly de-ionizing and extinguishing an intense arc. During the existence of the arc, high temperature gases are generated which must exit from the line side of the circuit breaker enclosure in order to prevent the circuit breaker enclosure from becoming over-stressed. During the arc occurrence, some means must usually be employed to prevent the ionized gases from contacting the associated grounded enclosure to thereby prevent the occurrence of a so-called "line-to-ground" fault. Further means must be employed to prevent the arc gases exiting from one line terminal compartment from contacting a line terminal connector within an adjacent line terminal compartment to prevent a so-called "phase-to-phase" fault.
U.S. Pat. No. 4,639,564 describes one such means integrally-formed within the circuit breaker cover to prevent the arc gases from causing electrical breakdown between a terminal and a proximate conductor.
It would be advantageous, for manufacturing and operating purposes, to provide controlled egress of the arc gases during circuit interruption while simultaneously preventing access to the line terminals when the circuit breaker is installed within the associated industrial power distribution circuit.
This invention accordingly provides a combined means for preventing access to the line terminals while simultaneously controlling the egress of arc gases from the circuit breaker enclosure.